(19)
(11)EP 1 132 866 A3

(12)EUROPEAN PATENT APPLICATION

(88)Date of publication A3:
02.07.2003 Bulletin 2003/27

(43)Date of publication A2:
12.09.2001 Bulletin 2001/37

(21)Application number: 01105263.6

(22)Date of filing:  05.03.2001
(51)Int. Cl.7: G06T 17/30
(84)Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
Designated Extension States:
AL LT LV MK RO SI

(30)Priority: 06.03.2000 JP 2000059930

(71)Applicants:
  • Being Co., Ltd.
    Tsu-shi, Mie-ken (JP)
  • CITEC Corporation
    Anjyou-shi, Aichi-ken (JP)
  • Yoshida, Yasuhiko
    Anjyou-shi, Aichi-ken (JP)

(72)Inventors:
  • Yoshida, Yasuhiko
    Anjyou-shi, Aichi-ken (JP)
  • Shiiba, Eiji
    Anjyou-shi, Aichi-ken (JP)

(74)Representative: TER MEER STEINMEISTER & PARTNER GbR 
Artur-Ladebeck-Strasse 51
33617 Bielefeld
33617 Bielefeld (DE)

  


(54)Three-dimensional topology-based CAD system


(57) According to the 3D-CAD system of the present invention, basic graphic elements (PL, LL, SL, VL) are set based on linear, area or volume coordinate parameters, and the plurality of basic graphic elements are continuously connected to generate a basic graphic. The basic graphic elements constituting the generated basic graphic are continuously differentiable even after deformation, thereby generating a desired solid graphic (identical topology graphic). By using these patches for approximately expressing all surfaces, the surfaces are handled consistently, the data quantity describing the graphics is greatly reduced, and the load of operational processing of the computer is reduced. Whether or not an element can be deleted is determined based on a reference counter RC showing whether said element is the component of another element.